Many frozen confectionery products are known. Increasingly, there is a consumer demand for composite products formed from different edible materials in complementary combinations in the premium category. One desirable combination is ice cream stick bar with chocolate coating which gives a contrast of texture between the crispy chocolate and the soft aerated ice cream. There are, however, significant production difficulties involved in the integration of these materials in various shapes and sizes to produce interesting new products in a consistent and cost-effective manner.
Frozen confectionery stick bars are manufactured on an industrial scale by means of moulding or by means of extrusion.
The extrusion method of forming chocolate based frozen stick bars is to provide a core of aerated frozen confection out of a freezer by vertical extrusion of an extrudate from an extrusion die onto refrigerated plates, cutting the extrudate into slabs of oval section while inserting a stick from the side, hardening the slabs in a cold air tunnel, taking out the slabs from the supporting plates by the sticks and dipping them into a bath of fat based coating, e.g. chocolate. When extrusion is employed, a sausage shape of plastic consistency, which is relatively hard at a temperature of the order of −6° C. to −7° C., is produced. Extrusion gives the products a fine, less crystallized texture than that of moulded products. The fine texture obtained by means of extrusion is largely due to the freezing conditions in a freezer and, in particular, to the freezing temperature at the exit from the freezer. That is to say, the lower the temperature, the fewer large crystals are formed. This means that the faster the freezing, the smaller the ice crystals and the finer the texture. One disadvantage of that method is that very limited shapes can be produced and the aspect and the definition of the surface of the coated product are generally poor. In addition there are problems associated with dipping, such as irregular thickness of the coating, cracking and bleeding.
Another known method of forming chocolate based confectionery products involves moulding. It comprises pouring or spraying molten chocolate into a female mould, and then pouring off the excess such that the residual material hardens around the inner surface of the mould in order to create a chocolate shell. One disadvantage of this technique is that the results are highly dependent upon the viscosity of the molten chocolate, which can vary with composition, as well as temperature and ambient humidity. This makes it difficult to regulate precisely how much material adheres to the mould, and hence the amount of excess material that will be poured off. Consequently, it is difficult to predict the wall thickness and mass of the finished product. A further problem is that the method often gives rise to a non-uniform wall thickness in the product, due to the pooling of molten chocolate toward the lowermost part of the mould.
A liquid composition is then generally poured into the mould where it is frozen. The freezing of the liquid composition to be frozen by means of moulding through simple thermal conduction in a mould immersed in a refrigerating solution is slow and leads to the formation of considerably large crystals. In this process, the composition to be frozen is always metered out in the liquid state into moulds with a view to guaranteeing satisfactory filling and to preventing the creation of air pockets, and its temperature is of the order of −2° C. to −3° C. The proportion of frozen water is low and most of the process of freezing the product takes place in the moulds. This explains the presence of a coarse, more crystallized texture, owing to an increase in the size of the crystals.
A method for producing ice cream stick bars coated with chocolate by moulding is disclosed in US 2002/0146496 and in US 2002/0149488. The objective of this method is to avoid the disadvantages of known moulding methods using brine cooling equipment in which an insulating air casing is created between the mould wall and the formed chocolate layer that considerably slows down the freezing process. It comprises filling pre-cooled moulds with chocolate until a layer of chocolate is formed against the mould wall, back-sucking the liquid chocolate core to create a cavity, filling the mould lined with chocolate with a pasty, i.e. non frozen ice cream mix, chilling the upper surface in an air tunnel provided with nitrogen to create a plug for closing the cavity which thus avoids vertical expansion of the filling on freezing and instead directs the ice cream filling toward the mould wall for better efficiency in the completion of the freezing in a brine bath.
It is the object of the present invention to improve the moulding of coated frozen confectionery products.
This object is achieved by means of the features of the independent claims.
The dependent claims develop further the central idea of the invention.